I'll give the most frustrating answer - time.
It is super tempting to just get in there and get it going quickly, but if he is hiding away he still needs time to adjust. Two days is really not long so it will probably be quite a bit longer before you get to the point where you can start building trust. First he needs to find his feet and get comfortable, then he might be ready to get to know you.
Let him know you're there, talk to him and put your scent on some paper bedding in his habitat.
With time he might come around to you when he feels more confident and at home. Watch his behaviour and you'll know what little changes happen.
So, time and patience.
Best of luck!